cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A285106 a(n) = A001222(A284576(n)).

Original entry on oeis.org

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Offset: 0

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Author

Antti Karttunen, Apr 11 2017

Keywords

Crossrefs

Programs

  • Scheme
    (define (A285106 n) (A001222 (A284576 n)))
    ;; A more practical version, needing only an implementation of A003986bi (bitwise-or, A003986) and memoization-macro definec:
    (define (A285106 n) (apply + (bitwise_or_of_exp_lists (A260443as_coeff_list n) (A260443as_coeff_list (+ 1 n)))))
    (define (bitwise_or_of_exp_lists nums1 nums2) (let ((len1 (length nums1)) (len2 (length nums2))) (cond ((< len1 len2) (bitwise_or_of_exp_lists nums2 nums1)) (else (map A003986bi nums1 (append nums2 (make-list (- len1 len2) 0)))))))
    (definec (A260443as_coeff_list n) (cond ((zero? n) (list)) ((= 1 n) (list 1)) ((even? n) (cons 0 (A260443as_coeff_list (/ n 2)))) (else (add_two_lists (A260443as_coeff_list (/ (- n 1) 2)) (A260443as_coeff_list (/ (+ n 1) 2))))))
    (define (add_two_lists nums1 nums2) (let ((len1 (length nums1)) (len2 (length nums2))) (cond ((< len1 len2) (add_two_lists nums2 nums1)) (else (map + nums1 (append nums2 (make-list (- len1 len2) 0)))))))

Formula

a(n) = A001222(A284576(n)).
a(n) = A285107(n) + A285108(n).
Other identities. For all n >= 0:
A007306(1+n) = a(n) + A285108(n).